Daniela Ruah was born in Boston, Massachusetts, to Portuguese-born parents, Katharina Lia Azancot Korn and Moisés Carlos Bentes Ruah, a doctor. She lived in the US until she was five. Her father's family is Sephardi Jewish, while her mother is of mostly Ashkenazi Jewish, along with Spanish and Sephardi Jewish, ancestry. Daniela attended St. Julian's School in Portugal, where she grew up, landing her first acting role at the age of 16. She kept working on diverse projects and finished high school. At the age of 18, Daniela moved to London, England to do a B.A. in Performing Arts at the London Metropolitan University, having finished with first class Honors. In 2007, she moved to New York to study at the Lee Strasberg Theatre and Film Institute.